Abstract

The Eastern Layered Series of the Rhum ultrabasic compkx formed in situ, and was not tectonically emplaced as previously suggested. Field relations along the contact show no evidence for the existence of a late 'Marginal Gabbro', instead peridotite and allivalite layers can be traced to within 2m of the surrounding partially melted
country rocks. Local preservation of a chilled margin to one peridotite layer indicates that the parental magma consisted of an olivine tholeiite liquid carrying approximately 19% (vol.) olivine crystals in suspension.